A conventional hydraulic piping fixing device for a construction machine in accordance with the prior art shown in FIG. 1 includes:
a piping seat 2 weldingly fixed to an upper plate of a boom structure 1 such as an excavator;
a hydraulic piping 3 (e.g., hydraulic piping for an arm cylinder) seated on the piping seat 2;
a steel clamp 5 having semi-circular shaped seating grooves formed therein to support the hydraulic piping 3; and
a fastening member 6 configured to fasten the steel clamp 5 to the piping seat 2 to allow the hydraulic piping 3 to be securely fixed by the steel clamp 5 and the piping seat 2.
In this case, the hydraulic piping 3 is a metal pipe that is join-connected to a main piping (e.g., hydraulic hose) through a connector 9 mounted on an outlet side of the main piping connected at an inlet side thereof to a main control valve (MCV) 7 mounted on the upper swing structure.
As described above, if a quarry work or breaker work is performed in a state in which the hydraulic piping 3 is securely fixed to the boom structure, since vibration occurring due to an external shock is directly transferred to the hydraulic piping 3 and the steel clamp 5, leakage of hydraulic fluid occurs through a crack formed on the hydraulic piping 3 due to frequent vibration.
Meanwhile, the conventional hydraulic piping fixing device entails a shortcoming in that since the fastening member 6 is loosened from the piping seat 2 due to vibration, and the fastening member 6 loosened due to the repeated work may escape from the piping seat 2, the device is very vulnerable to vibration. Despite the disadvantage of causing damage to the machine image due to degradation of quality by the loosening of the fastening member 6 that fastens the steel clamp 5 to the piping seat, the conventional hydraulic piping fixing device constructed as an inexpensive structure is still applied to some construction sites.
FIG. 2(a) is a side view of a boom structure, and FIG. 2(b) is a cross-sectional view taken along the line A-A of FIG. 2(a).
Another conventional hydraulic piping fixing device for a construction machine in accordance with the prior art shown in FIGS. 2(a) and 2(b) includes:
a piping seat 2 weldingly fixed to an upper plate of a boom structure 1 of an excavator;
a lower clamp 10 seated on the piping seat 2;
a hydraulic piping 3 (e.g., hydraulic piping for an arm cylinder) seated on seating grooves symmetrically formed on the left and right sides of the lower clamp 10;
an upper clamp 11 configured to securely fix the hydraulic piping 3 seated on the lower clamp 10; and
a fastening member 12 configured to fasten the upper clamp 11 to the lower clamp 10 to allow the hydraulic piping 3 to be securely seated on the seating grooves of the upper and lower clamps 11 and 10.
Thus, since the hydraulic piping 3 is securely fixed in a state of being not brought into direct contact with the piping seat 2, a problem associated with occurrence of vibration during the work can be overcome.
In the meantime, the conventional hydraulic piping fixing device encounters a problem in that the fastening member 12 is loosened due to vibration occurring during the quarry work or the like to cause the hydraulic piping 3 to droop in a state in which the hydraulic piping 3 is connected to the main piping 8 by means of a connector 9 and then is mounted on the upper plate of the boom structure 1.
More specifically, the main piping 8 (e.g., hydraulic hose) connected to the main control valve (MCV) mounted on the upper swing structure of the excavator and the hydraulic piping 3 mounted on the upper plate of the boom structure 1 are connected to each other using the connector 9 so as to be fit for a hydraulic circuit. Thus, the arm cylinder can be driven by a hydraulic fluid supplied from the main control valve 7 through the main piping 8 and the hydraulic piping 3.
In this case, the fastening member 12 is gradually loosened due to vibration occurring during the quarry work and thus the fastening state of the upper clamp 11 that securely fixes the hydraulic piping 3 is also released gradually. Thus, the main piping 8 forcibly pulls the hydraulic piping 3 toward the upper swing structure to cause the hydraulic piping 3 to droop.
The reason for this is that the boom structure 1 rotatably connected to the upper swing structure by the boom fixing pin 13 is pivotally driven along a given trajectory about a boom fixing pin 13 in a vertical direction, at which time, the fastening member 12 that securely fixes the upper clamp 11 to the lower clamp 10 is loosened due to vibration to cause the clamping force of the upper clamp 11 to the lower clamp 10 to be weakened.
For this reason, the main piping 8 connected to the main control valve 7 forcibly pulls the hydraulic piping 3 securely fixed between the lower clamp 10 and the upper clamp 11 to cause the hydraulic piping 3 to droop.
As described above, the hydraulic piping 3 is maintained in a state of being aligned in a straight line at an early stage in which the hydraulic piping 3 is securely mounted on the boom structure 1. However, there is caused a problem in that when the hydraulic piping 3 droops due to vibration occurring during the work, the non-matched assembly position is exposed, thereby degrading an outer appearance image of the construction machine.
For this reason, the fastening member 12 is designed to have a size larger than a reference size in order to prevent the fastening member 12 from drooping due to vibration occurring during the work. Alternatively, a separate clamp is installed in order to prevent the fastening member 12 from drooping, which leads to an increase in the number of parts, thereby deteriorating assembly workability.